It would be helpful for an administrator to be able to define custom interface types (beyond just Agent, SNMP, JMX, etc).  Our current need is for an SSL/TLS interface type, but rather than addressing each new type individually, it makes more sense to add flexibility and allow Zabbix administrators to configure what types they need.

Use cases:

1 - We have servers that host multiple web sites, and we would like to monitor the SSL expiration on each (among other things).  Since discovery can now be based on host interfaces, it would be nice to be able to add each URL as an interface of type SSL (or something like that), and let the discovery mechanism add templated monitoring for each site.

2 - There are other requests for things like a Generic/Dummy interface for hosts that only use simple checks.  This functionality would resolve that need.

3 - If the fields for the interface type were also made customizable (ie: not just IP, DNS, port), then this same mechanism could be used to specify things like multiple databases housed on the same server, multiple tomcat instances.  Basically this would allow for templated monitoring of any application that may run multiple instances or offers separate services on the same host.